The head of the Democratic National Committee on Tuesday mocked the Trump administration’s claim that the indictments and a guilty plea this week from members and advisers to the Republican’s 2016 campaign has nothing to do with the president, saying there is now “clear evidence” of collusion with Russia. Speaking at a breakfast sponsored by the Christian Science Monitor, Tom Perez, who took over the troubled DNC this year, said the indictments of former campaign chairman Paul Manafort and longtime associate Rick Gates, as well as the guilty plea from George Papadopoulos, who served as a foreign policy adviser, show...